The present application is based on and claims priority under 35 U.S.C xc2xa7119 with respect to Japanese Patent Application No. 2000-283364 filed on Sep. 19, 2000 AD (12th year of Heisei), the entire content of which is incorporated herein by reference.
The present invention is generally directed to a vehicular lamp control apparatus which feeds electric power (i.e. voltage) to one or more lamps from a high voltage battery.
Recently, optional electrical equipment on vehicles and/or the vehicles per se are high-performance, which results in an increase of electric power consumed. Thus, the conventional inner-vehicle electric power system using a 12V battery is deficient in electric power supply. In addition, due to the increasing of the number of the aforementioned electrical components, an amount of current flowing through a harness becomes larger and larger which connects each of the electrical components and the battery, with the result that how to cope with the resultant or increased amount of heat generation becomes a serious problem.
One of the proposed solutions is to shift to a newly established rating which includes increasing the voltage of the battery to a higher value, for example, 36 volts.
If the higher-voltage battery is employed, the currently used lamps which operate on 12 volts cannot be lit by the conventional method.
The present invention has been developed to satisfy the request noted above and a first aspect of the present invention provides a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery one after another in periodic fashion, the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that all the voltage amounts are detected by a sole device, and when one of the voltage amounts exceeds a threshold value, a dead band is expanded which is defined between the corresponding time duration and a subsequent time duration. In accordance with the first aspect of the present invention, if the voltage amount to be supplied to the lamp exceeds the threshold value, the dead band is expanded which is defined between the corresponding time duration and the subsequent time duration. When the plural lamps are supplied with the voltages, respective, one after another in periodic fashion, sometimes an overlap may occur between a specific lamp and the subsequent lamp in voltage supply due to the delay action for the former, which results in a temporal increase of a total of the voltages supplied to the respective lamps. However, even if the voltage amount to be supplied to the lamp exceeds the threshold value, the dead band is expanded which is defined between the corresponding time duration and the subsequent time duration, thereby making the aforementioned overlap as short or small as possible. Thus, the aforementioned temporal voltage increase is restricted, which restricts the generation of a surge following a sudden change in supply voltage or current, thereby reducing the electromagnetic noise upon the electric power supply.
A second aspect of the present invention is to provide a vehicular lamp control apparatus which is a modification of the structure of the first aspect, wherein supplying the voltages to the respective lamps are made in different order for reducing the supply voltage amount variation. In accordance with the second aspect of the present invention, supplying the voltages to the respective lamps is made in a different order for reducing the supplying voltage amount variation. Correspondingly, the frequency of adjusting the voltage amount is made less, thereby reducing the surge as small as possible.
A third aspect of the present invention is to provide a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery one after another in periodic fashion, the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that the lamps are divided into two groups and if a malfunction is found in voltage supply in one group, the voltage supply is switched to the other group. In accordance with the third aspect of the present invention, even if a voltage supply malfunction is found at the lamp in one group, a timely or quick action can be taken by activating the normal lamp in the other group.
A fourth aspect of the present invention is to provide a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery in periodic fashion, the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that when an automatic engine stop control becomes active the time duration for the lamp is gradually decreased and/or when an automatic engine start control becomes active the time duration for the lamp is drastically increased. In accordance with the fourth aspect of the present invention, when the automatic engine stop control becomes active, the time duration during which the lamp is being supplied with the voltage is gradually decreased, thereby making the lamp darken gradually and naturally and restricting the consumed electric power. In addition, when the automatic engine start control becomes active, the time duration during which the lamp is being supplied with the voltage is drastically increased, thereby ensuring the required illumination of the lamp when the vehicle begins to start.
A fifth aspect of the present invention is to provide a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery in periodic fashion, an amount of the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that the time duration is corrected to increase or decrease on the basis of at least one of ambient brightness, a vehicle speed, and a voltage of the high voltage battery. In accordance with the fifth aspect of the present invention, if the time duration during which the lamp is being supplied with the voltage is corrected to increase or decrease on the basis of the ambient brightness, for example, when the ambient brightness is light, making the time duration during which the lamp is being applied with the voltage shorter correspondingly brings in the restriction in consumed electric power without disturbing eyesight. In addition, if the time duration during which the lamp is being supplied with the voltage is corrected to increase or decrease on the basis of the vehicle speed, for example, when the vehicle speed is slow, making the time duration during which the lamp is being supplied with the voltage shorter correspondingly brings in a restriction in consumed electric power. Moreover, if the time duration during which the lamp is being supplied with the voltage is corrected to increase or decrease on the basis of the voltage battery, for example, when the voltage battery is low, making the time duration during which the lamp is being supplied with the voltage longer correspondingly ensures the required illumination of the lamp.
A sixth aspect of the present invention is to provide a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery in periodic fashion, an amount of the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that there is provided communication means receiving identification information transmitted from a mobile communication device and detecting whether or not the received identification information is in coincidence with pre-stored owner""s identification information, and the voltage supply to the lamp is initiated in a predetermined manner when the received identification is found to be in coincidence with the pre-stored owner""s identification information, even if an ignition switch is OFF. In accordance with the sixth aspect of the present invention, when the identification information transmitted from the mobile communication device is found to be in coincidence with the prestored owner""s identification information even if the ignition key is OFF, the voltage supply to the lamp is initiated in the predetermined manner. Thus, in a large parking area, sending the identification information from the mobile communication device to the communication means causes the lamps to flash on-and-off, which makes it possible to recognize easily where the vehicle is parked.
A seventh aspect of the present invention is to provide a vehicular lamp control apparatus which comprises a high voltage battery and a plurality of lamps, the lamps being supplied with voltages, respectively, from the high voltage battery in periodic fashion, an amount of the voltage supplied to each of the lamps being controlled by adjusting a time duration during which each of the lamps is supplied with the corresponding voltage by PWM control, characterized in that there is provided theft detection means for detecting whether or not the vehicle is in danger of theft the voltage supply to the lamp is initiated when the vehicle is found to be in danger of theft, even if the ignition switch is OFF. In accordance with the seventh aspect of the present invention, when the vehicle is found to be in danger of theft, even if the ignition key is OFF, the voltage supply to the lamp is initiated in the predetermined manner, which causes the lamps to flash on-and-off, thereby making it possible to inform everyone that the vehicle is being in danger of theft or being stolen.